Baseball, Class and Community in the Maritime Provinces, 1870-1910

The study of baseball permits detailed analysis of class relations, gender roles and community identity during the industrial transformation of the late nineteenth century. Drawing upon Raymond Williams concept of "the social relations of cultural production", this article explores how the development of baseball was linked to Victorian notions of respectability, and to the growing discourse associated with the public organization of play and leisure. In particular, the interpretation focusses on the Maritimes where reformers, entrepreneurs, gamblers, working people, athletes and spectators used unpredictable ways to shape the game to meet their own needs. L’étude du baseball favorise l’analyse détaillée des rapports sociaux, des rôles sexuels et de l’identité communautaire au moment de la révolution industrielle du XIXe siècle. S’inspirant de la théorie de Raymond Williams sur « les relations sociales issues de la production culturelle », l’auteur examine ici les liens entre le développement du baseball et les notions victoriennes de respectabilité et le discours de plus en plus répandu sur l’organisation publique des jeux et des loisirs. Il s’intéresse plus particulièrement aux provinces maritimes où les réformateurs, les entrepreneurs, les travailleurs, les athlètes et les spectateurs ont recouru à des moyens inattendus pour donner à ce jeu une forme susceptible de satisfaire leurs besoins propres

Shape optimization of pressurized air bearings

Use of externally pressurized air bearings allows for the design of mechanical systems requiring extreme precision in positioning. One application is the fine control for the positioning of mirrors in large-scale optical telescopes. Other examples come from applications in robotics and computer hard-drive manufacturing. Pressurized bearings maintain a finite separation between mechanical components by virtue of the presence of a pressurized flow of air through the gap between the components. An everyday example is an air hockey table, where a puck is levitated above the table by an array of vertical jets of air. Using pressurized bearings there is no contact between “moving parts” and hence there is no friction and no wear of sensitive components. This workshop project is focused on the problem of designing optimal static air bearings subject to given engineering constraints. Recent numerical computations of this problem, done at IBM by Robert and Hendriks, suggest that near-optimal designs can have unexpected complicated and intricate structures. We will use analytical approaches to shed some light on this situation and to offer some guides for the design process. In Section 2 the design problem is stated and formulated as an optimization problem for an elliptic boundary value problem. In Section 3 the general problem is specialized to bearings with rectangular bases. Section 4 addresses the solutions of this problem that can be obtained using variational formulations of the problem. Analysis showing the sensitive dependence to perturbations (in numerical computations or manufacturing constraints) of near-optimal designs is given in Section 5. In Section 6, a restricted class of “groove network” designs motivated by the original results of Robert and Hendriks is examined. Finally, in Section 7, we consider the design problem for circular axisymmetric air bearings

Diastereoselective Cyclizations of Enantiopure Planar Chiral N-Oxazolidinoyl Diene Iron(0) Tricarbonyl Complexes

Iron(0) tricarbonyl diene complexes have long been established as effective stereodirecting groups due to their planar chirality and the steric bulk of the iron fragment. If initial diastereoselective complexation can be achieved, these molecules are therefore capable of acting as scaffolds for the stereoselective synthesis of architecturally complex products. The Paley laboratory uses chiral auxiliaries, most recently oxazolidinones, bound to acyclic dienes to assure diastereoselective complexation, before exploring the potential of diverse diastereomeric chemistry on the diene periphery. In this work we report progress on the development of an asymmetric, intramolecular rhodium(II)-catalyzed C-H insertion adjacent to the diene to form five- membered carbocycles with two determined stereocenters. In particular, we discuss the synthesis of N-oxazolidinoyl diene iron(0) tricarbonyl complexes containing both protected alcohol and indole functionalities, followed by diastereoselective cyclization to form the corresponding cyclopentenes upon addition of the rhodium catalyst. Additionally, initial steps towards the optimization of these synthetic pathways, including the exploration of alternative methods to install the requisite diazo group, are detailed in this report. It is predicted that these transformations will ultimately enable synthetic access to new classes of natural products

Solar sail dynamics in the three-body problem: homoclinic paths of points and orbits

In this paper we consider the orbital previous termdynamicsnext term of a previous termsolar sailnext term in the Earth-Sun circular restricted three-body problem. The equations of motion of the previous termsailnext term are given by a set of non-linear autonomous ordinary differential equations, which are non-conservative due to the non-central nature of the force on the previous termsail.next term We consider first the equilibria and linearisation of the system, then examine the non-linear system paying particular attention to its periodic solutions and invariant manifolds. Interestingly, we find there are equilibria admitting homoclinic paths where the stable and unstable invariant manifolds are identical. What is more, we find that periodic orbits about these equilibria also admit homoclinic paths; in fact the entire unstable invariant manifold winds off the periodic orbit, only to wind back onto it in the future. This unexpected result shows that periodic orbits may inherit the homoclinic nature of the point about which they are described